1. Field of the Invention
The present invention relates to a semiconductor package and a method of manufacturing the semiconductor package, and more particularly, to a semiconductor package in which a bonding pad of a semiconductor chip is electrically connected to an interconnection portion of the semiconductor package by wire bonding, and a method of manufacturing the semiconductor package.
2. Description of the Related Art
Electronic appliances are becoming smaller, higher capacity, and increasingly multi-functional, largely owing to the continued development in the field of semiconductor integration technology and electronic engineering. One example showing this development is commercialization of portable multi-media reproducing devices, mobile phones, or various other digital appliances or devices in which functions of both of the above appliances are converged. Such digital devices, which need to be miniaturized and at the same time capable of performing multiple operations, are realized by high integration packaging technologies—such as chip scale package (CSP), system on chip (SOC), or multi-chip package.
In the case of the above high integration package technology, a semiconductor chip in the packages can be electrically connected directly to outer interconnections with solder bumps, so as to simplify an interconnection process. However, the interconnection process with the solder bumps in CSP package cannot provide such a reliable and economical interconnection as a conventional wire bonding process. So, the wire bonding process is commonly adapted to the high integration packaging technologies.
FIG. 1 is a perspective view illustrating a conventional semiconductor package 50 using a conventional wire bonding process, and FIG. 2 is a top view illustrating conventional contact pads 20 illustrated in FIG. 1.
Referring to FIGS. 1 and 2, interconnection portions 20R comprise a plurality of contact pads 20, which are separated a predetermined distance from each other and electrically isolated from each other. Contact pads 20 are arranged on a substrate 10, for example, a printed circuit board or a ceramic substrate. A semiconductor chip 30 can be attached on the substrate 10 by an adhesion layer (not shown). Bonding pads 31 are arranged on edge portions of the semiconductor chip 30 for inputting and outputting power and signals. The bonding pad 31 is electrically connected to the contact pad 20 by a wire 40. As is well-known in the art, in a wire bonding process, an end portion of the wire 40 is bonded to the contact pad 20 with wire ball 40a using a capillary (not shown), and then the other end portion of the wire 40 is bonded to the bonding pad 31 of the semiconductor chip 30 so that the bonding pad 31 and the contact pad 20 can be electrically connected.
The number of contact pads 20 and wires 40 corresponds to the number of input and output signals required to drive the semiconductor chip 30, and as described above, according to the trend of higher capacities and multi-functions of electronic products, the number of the contact pads 20 and wires 40 is gradually increasing. However, a pitch P of the contact pads 20 and a width W of the contact pads 20 are being reduced according to the demand of the miniaturization of electronic products.
During the wire bonding process, for a wire ball 40a to provide a reliable bonding property between the contact pad 20 and the wire 40, a diameter R of the wire ball 40a is required to be of a specific critical value or greater. In order to reduce the pitch P of the contact pad 20, a wire 40 having a small diameter can be used to reduce the critical value of the diameter R of the wire ball 40a. However, as the diameter of the wire decreases, a sweeping phenomenon of the wire 40 is caused during the subsequent transfer molding process of an epoxy resin, which can cause short circuit between the wires 40. Thus, there is a limitation in reducing the critical value of the diameter R of the wire ball by reducing the diameter of the wires 40.
Recently, the pitch P of the contact pad has been minimized due to the miniaturization of the electronic products; however, since the diameter of the wire ball 40a needs to be maintained at or greater than the critical value, electrical short circuit between neighboring contact pads 20 are frequently generated by the wire ball 40a during the wire bonding process. Accordingly, the number of defects of final products is increasing, and high precision wiring equipment for resolving this problem is becoming a serious factor in increasing manufacturing costs.